Absolute spectrophotometry of SN 1987A and the H-alpha Bochum event.

Spectrophotometric optical fluxes of SN 1987A have been measured at high accuracy with the 61 cm telescope equipped with a rapid spectrum scanner. The H-alpha line shows a undisturbed P Cygni-type profile until March 15, superimposed by variable fine-structure thereafter, developing within a few days into a blue-shifted, peak-like flux excess and a red-shifted flux deficiency. A similar fine-structure is also observed in Na I-D, in Paschen-alpha and possibly in H-beta. The observations are discussed in terms of the 'mystery spot', and models involving a jet and interactions with surrounding preexisting material.